Refining hydrocarbon distillates



H. Pl-:AsE

May 10, 1932.

REFINING HYDROCARBON u DI STI'LLATES Filed July 7. 1927 .NS sbg@ Snow/woz @5% y@ www Mmm@ Patented May 10, 1932 UNITED STATES PATENT orifice HARRY PESE, OF BARNSDALL, OKLAHOMA, ALSSIGNOR T0 THE GRAY PROCESSES COR- PORATION, F NEWARK, NEW JERSEY, .A CORPORATION 0F DELAWARE REFINIING HYDROCARBON DSTILLATES Application tiled July 7, i927. Serial No. ZOSS.

i. removed therefrom in liquid orm, after which they are preferably reuxed to the still. 'llhe treated vapor freed from the unstable unsaturated compounds is collected and stored.

After a period of use, the efficiency ot the treating materialdecreases, probably due to the collection therein of substances which adhere to it and clog its active surfaces. Such decrease in etliciency is manites'tedby a decrease in the quality ot the treated vapor. This usually occurs progressively during the A treating process until ultimately the quality of the treated product becomes poorer than is desirable. Heretofore it has been the practice at this point either to discontinue operation or by appropriate valves to cause the vapors to contact with a different batch of treating material, the used treating material being revivitied for further use. Such procedure is not always convenient, especially when the treating process is being carried on under pressure in connection with a cracking unit for the purpose of treating cracked products. y

An object of this invention is to increase the eilicient life of solid adsorptive material used in the reiining of hydrocarbon products, thereby greatly increasing the efficiency of the refining process and decreasing the cost of the treating material.

According to this invention, when the treating material is apparently spent, as evi- -denced by appropriate tests of the treated vapor, the treating material is. reactivated by reducing temporarily the pressure on the fluids emerging from the treatingtmaterial'. rllhe reactivation oit the treating material is apparently caused by the solvent e'ect oit the more rapidly released vapors and liquids, although the exactreason for the reactivation is not known. This method of reactivation may 'apparently be'carried on practically indefinitely and by use of the method it has been possible to prolong the active lite of tullers earth in a treating tower connected with a Cross cracking unit until approximately seven thousand barrels of gasoline have been refined by each ton of earth, whereas previously, using the same stock and apparatus, only twelve hundred barrels could be refined before discarding the 'ullers earth.

Other objects, novel features and advantages oit the invention will be apparent :trom

the following description and accompanying drawings, wherein Figure l is a diagrammatic illustration oi i an apparatus for producing cracked gasoline in which ythe invention is embodied; and

Fig. 2 is an enlarged view ot a modified form of one ot the unit-s of the apparatus.

10 designates the furnace or tubekstill of a cracking unit to which the charging stock is supplied through a pipe 11. rllhe still 10 is connected by means of a pipe 12 with the reaction chamber 13,v which in turn is connected through the pipe 14: controlled by valve 15 with the vaporizer 16. A pipe 17 leads from the top of the vaporizer 16 to the dephleg mator 18 which preferably is a bubble tower.

From the top ot the bubble tower 18, a pipe 19 controlled by valve 20 communicates with the top ot a treating tower 21. Within the treating tower is provided a tunnel-shaped shelf 22 which supports a body of solid adsorptive material, such, for example, as fullers earth or the like. Huid-permeable and terminates in a spout 24 projecting beyond the bottom of the tower 2l. A pipe 25 controlledvby valvel 26 leads from the treating tower 21 at apoint below the' shelf 22 to a condenser 27 which communicates through a pipe 28 with a gas separator 29 which is provided with a valve-controlled vent 30. A pipe 31 leads from the gas separator 29 to a storage tank, not shown.

The shelf 22 is A pipe 32 leads from the bottom of the treating tower 21 to the lower portion of a tank or accumulator 33. A pipe 34 controlled by valve 35 leads from thelower portion of the accumulator The pump 36 communicates through a ipe 37 controlled b a valve 38 with the bu ble tower 18 and tli7 by a valve with the vaporizer 16. The accumulator 33 also communicates through the pipe 41 controlled by valve 42 with a cooler 43, which in turn communicates with a tank 44. The accumulator 33 is provided with a liquid regulator which controls the operation of the pum 36. In Fig. 2, the accumulator 33 is di erently connected than the accumulator 33 of Fig. 1. The pipes 32 and 34 are at the same level as in Fig. 1. The pipe 41 leadin to the cooler is, however, arranged near the upper part of the accumulator.

In the operation of this apparatus, charging stock -is supplied to thestill 10 from which it flows to the reaction chamber 13 and thence to the vaporizer 16 by way of the pipe 14 and valve 15. Vaporized hydrocarbons pass through the pipe 17 to the bubble tower 18 where the higher boiling constituents are condensed. The desired fraction, which maybe gasoline having a definite boiling range, is led in vapor form through the pipe 19 to the treating tower 21 where it is caused to pass through the solid adsorptive treating material 23. In its passage through the treating material, the unstable unsaturated hydrocarbons present therein are .polymerized to higher boiling compounds which condense in the treatin material. The treated vapor passes throng the pipe 25 to the condenser 27, from thence to the gas separator I29, and is then led by the pipe 31 to suitable storage tanks. The polymers collected in the treating material as well as any other condensate found therein drip through the treating material and collect in the bottom of the treating. tower 21 from which the are conducted by means of the pipe 32 to the accumulator 33. From the accumulator 33, the polymers andany other liquid that may have been collected with them are relluxed back into the system by means of the pump 36. The operation of the pump 36 is controlled by the regulator 45 so that -suiiicient liquid is kept in the accumulator 33 to act as a seal to prevent treated vapor escaping by way of the pipe 32. The cracking unit herein disclosed delivers the vaporized hydrocarbons to the bubble tower at a pressure in excess of atmospheric which pressure is normally maintained inthe treating tower and condenser as well as in the accumulator by proper regulation of the valves 28 and 35, valve 42 being closed.

After a period of operation, the treating material begins to lose its efliciency. Even- 33 to a pump 36.

rough the pipe 39 controlled tually, its eiiciency will-become so low that the treated vapor is not satisfactory. The exact limit varies with different installations, and the critical point where the product falls below specification is determined by the use of Various well-known tests. lVhen this condition has developed, formerly it has been the practice to discontinue the How of vapor through the treating tower either by shutting down the cracking unit or more usually by passing the vapors through another tower. The spent treating material is then removed Vfor revivification and fresh materialv substituted. This is avoided in accordance with the present invention by opening the valve 42, thus putting the accumulator in commumcation through the cooler 43 with the tank 44 which is preferably maintained atv atmospheric pressure. In an apparatus of the type herein disclosed, the vapor in the treating tower is usually maintained under a pressure of approximately thirty pounds, which pressure is maintained in the con denser and in the accumulator. When the valve 42 is opened, the pressure differential thus established causes an increased vapor flow through the treating material, the vapor being carried ofi' from the treating tower through the accumulator to' the tank 44 together with polymers and other liquid. As the valve 42 is preferably small and there is a lag due to the height of treating material fin the tower 21, the pressure drop caused y standard, the above procedure is repeated.

The intervals at whichit is 'necessary to open the valve 42 become shorter and shorter as the run progresses, and 1t eventually becomes economical to remove the treating material from the treating tower for further reactivation as by reburning. By means of the 1nvention herein described, it has been possible to increase the active life of treating material from approximately twelve hundred barrels per ton to approximately seven thousand barrels per ton in treating cracked gasoline.

The operation of the apparatus when provided with the modified accumulator is quite similar. However, instead of both vapor and iiuid flowing to the tank 44, vapor alone flows to this tank. This is bacause of the fact that the pipe 41 leads from the accumulator at a point above the level maintained in the liquid in the accumulator. With either mod- Sil ification, however, there is an increased How of vapor through the treating material which Y ing tower ordinarily used in connection with a pair of active treating towers, and thus reduces the actual cost of the installation.

Although the invention has been disclosed and described in connection with an apparatus embodying a cracking unit of the type ordinarily known as the Cross cracking unit, it is not limited to use with such unit but can be used equally eectively in any case where cracked or other vapors are refined by contacting them with a treating material which becomes inactive due to the accumulation of impurities on its surface. 'lhe .beneicial @dect attained by the invention is due to the reduction of pressure on the efliuent uids while the pressure of the crude vapors supplied to the treating tower is maintained. ln the case of atmospheric pressure treating,

this can be accomplished by connecting the accumulator or tank la with a vacuum pump or other source of subatmospheric pressure. -`Where the accumulator tank is not provided with a liquid level control device, it may be advisable to shut off the pump 36 when the valve 42 is opened.

lt is apparent, of course, that various moditications may be made in the structural details of the apparatus above disclosed withtill from the spirit of out in any way departing \in the appended the invention as delined claims.

l. ln' the process ot treat-ing vaporized hydrocarbons by passing the same through solid adsorptive material, the step which comprises periodically increasing the pressure ,diii'erentlal through the adsorptive materialby reducingbhe pressure applied to the eiuent hydrocar ns materially below that applied to the entering hydrocarbons.

2. ln the process of treating vaporized hydrocarbons by passing the same through solid adsorptive material at super-atmospheric pressure, the step which comprises eripdically increasing the pressure d1 erential through the adsorptive material by reducing materially the pressure on the euent hydrocarbons while maintaining substantially undiminished the pressure of the entering hydrocarbons.

3. 'lhe process of treating vaporized hydrocarbons whichcomprises passm said hydrocarbons through solid adsorptrve material, maintainin super-atmospheric pressure on the entermg hydrocarbons and periodically 'increasing the pressure dilerential through the adsorptive material by reducing the pressure applied to the emuent hydrocarbons by causing a portion thereof to flow to a zone of atmospheric pressure.

4. rlhe method of prolonging the useful life of adsorptive treating material interposed in a hydrocarbon vapor stream in such manner that under normal operating'conditions both euent and entering vapors are subjected to substantially the same pressure which comprises periodically increasing the pressure dierential through the adsorptive material by materially reducing the pressure to which the emuent treated vapors are subjected.

5. 'lhe method of prolonging the useful life ot adsorptive treating material interposed in a hydrocarbon vapor stream in such manner that under normal operating conditions both emuent and entering vapors are subjected to at least atmospheric pressure which comprises periodically increasing the pressure differential through the adsorptive material by causing dow oi a portion of the euent vapors to a zone ot lower pressure than that to which they are normally subjected 6. The method ot prolonging the useful liie of adsorptive treating material interposed in a hydrocarbon vapor stream in such manner that under normal -operating condi, tions bot-h eluent and entering vapors are subjected to super-atmospheric pressure which comprises periodically increasing the pressure diderential through the adsorptive material by reducing to atmospheric the pressure applied to the euent vapors while maintaining substantially undiminished the pressure applied to the entering vapors.

7. The process of passing hydrocarbon vapors under pressure through a bed of adsorbent material, removing liquid products from said material, continuously separating emuent vapors from said liquids while maintaining super-atmospheric pressure thereon and periodically increasing the pressure ditterential through the adsorptive material by reducing the pressure on the euent vapors` for the purpose of reactivating said treating material.

8. The process of passing hydrocarbon valll@ lll@

pors through a bed of solid adsorptive mathat under normal opy ian iat v adsorptive material, normally maintaining super-atmospheric pressure on bothv the entering' and eiuent vapors, removing liquid products from said material, continuously separating the eHuen't vapors from said liquid products While maintaining super-atmospheric pressure thereon and periodically reducing the pressure ou the eiuent vapors to atmospheric. 4

.,Intestimony whereof, I have signed my name to this specification.

HARRY PEASE. 

